OBJECTIVES: 1) Following the destruction of the lateral geniculate nucleus, the slabs of striate cortex will be processed for electron microscopy. We plan to serially reconstruct a small spiny stellate cell of layer IV, which would receive contact from geniculocortical fibers upon its soma or proximal dendrites. 2) Following the injection of tritiated proline in area 18, terminals of the projection from area 18 upon the striate cortex will be identified by autoradiography at the electron microscopic level. BIBLIOGRAPHIC REFERENCES: M. Tigges, J. Box, J. Tigges and E. Breeding: Ultrastructure of striate cortex layer IV neuropil in squirrel monkey. Neurosci. Abstr. 2, 142 (1976). J. Tigges, J. Bos and M. Tigges: An autoradiographic investigation of the subcortical visual system in chimpanzee. J. Comp. Neur. 172, 367-380 (1977).